DIMINISHED DIURNAL BLOOD-PRESSURE VARIABILITY IN PREECLAMPSIA

Circadian blood pressure (BP) variability is altered in pregnancy-induced hypertension. Intermittent 24-hour BP monitoring allows the quantification of diurnal BP variations. Noninvasive 24-hour ambulatory BP monitoring was performed in 53 normotensive female volunteers (age: 28 +/- 9 yrs.), 30 females with primary hypertension without any signs of target organ damage (age: 42 +/- 11 yrs.) and 37 patients with pre-eclampsia (age: 28 +/- 4 yrs.). The Cosinor-method was employed to determine circadian amplitude and mesor of mean arterial BP (MAP) in each of the profiles respectively. Mean circadian amplitudes did not differ between patients with pre-eclampsia and normotensive females. However, the relation between mesor and amplitude was found to be significantly different in the group of pre-eclamptic patients (r = -0.47, p < 0.003) compared to normotensives (r = 0.34, p < 0.01) and hypertensive (r = 0.38, r < 0.04) females. We conclude that in uncomplicated female primary hypertensives and in normotensive females diurnal BP variations increase when 24-hour BP levels increase. In pre-eclampsia circadian MAP variability diminishes when mean 24-hour BP levels are increased. Quantification of circadian BP variations therefore might have diagnostic implications.